Investigation 2 Lecture January 4, 2016

There are many other forms of energy – elastic, chemical, electric, and thermal In this investigation we will focus on electrical potential energy which depends on the position of charges in relation to each other; when the charges move it becomes electrical kinetic energy!!

 Electrical energy starts as potential energy until a light is turned on and charges begin to move, then it turns into kinetic energy.  Notice that the electrons leave the battery at the minus (-) terminal and are redirected back to the positive (+) terminal.  The negatively charged electrons always move toward positive and away from negative charges.

 Light energy is kinetic energy because light consists of moving photons.  The more electrons that flow through a light bulb in a period of time, the hotter and brighter it will get.

 Most electricity is produced at a distance from a larger source  When we plug an appliance into the wall at home, we create a circuit and permit electrons to flow through the device.  The electrons flow through a wire and into the appliance.  Electrons flow through a wire from their source of production at a power plant.  Regardless of how the power is transmitted (solar, gas, coal, hydroelectric, wind, nuclear, etc.), the power reaches our homes and schools as a current of electrons and becomes available in a controlled manner from electrical “outlets”. When we plug an electrical cord into an outlet, we cause electrons to move and use their kinetic energy.

 Electrical energy will be measured in watts.  A watt is defined as one joule per second.  We will not measure wattage, but rather use the wattage that is stamped on the light bulbs.  Light will be measured in a unit know as the lux.  This is a measure of the amount of illumination per unit of surface area.  We will measure lux with a light meter.  Finally, we will measure temperature, in degrees Celsius ( o C) with a glass thermometer.

 Electrical energy Electrical energy  Start at 11 minutes